Young's modulus and tensile strength of CuNi(Mn) thin films on polyimide foils by tensile testing

Force-strain curves were measured for 1.0 mu m and 1.5 mu m thick Cu0.57Ni0.42Mn0.01 films on 8 mu m thick polyimide foils by tensile testing. By separating the force working on the polyimide foil from that working on the metal-polyimide compound, stress-strain curves for the CuNi(Mn) films were obtained. Young's modulus and tensile strength were determined for as-deposited and annealed [350 degrees C, 1 h, N-2/H-2 (5 vol %) atmosphere] films by this method. Crack propagation starts at the end of the elastic region at 0.2 to 0.7% strain, depending on the film thickness and the thermal treatment. The cracking behavior is described by a steady-state approximation.